Review of Savonius Wind Turbine Design and Performance

Mecánica

E. A. Salazar-Marín 1 edgarsalazar@utp.edu.co

Technological Academy of Pereira, Republic of colombia

A. F. Rodríguez-Valencia two afrodriguezv@uao.edu.co

Autonomous University of Occident, Colombia

Design, associates and experimental tests of a Savonius type wind turbine

Scientia Et Technica , vol. 24, no. 3, pp. 397-407, 2019

Universidad Tecnológica de Pereira

Received: 25 February 2019

Accepted: 23 September 2019

Abstruse: The present research project focuses on the development of a Savonius type air current turbine, where a literature review is initially carried out to recognize the advisable parameters for its design such as turbulence, wind velocity, and air density, followed by a design methodology to reach the dimensioning by means of resistance calculation and selection of component materials, after having the terminal concept defined. Through the use of computational tools such as Solidworks, Inventor, Simulation Mechanical, the design stage was validated through simulation to study the dynamic fluid behavior and the components were modeled to evaluate their response to air current loads, verifying their resistance. Later on, according to the modeling, the detailed drawings of the components of the turbine were obtained, with which they were assembled. Finally, having the physical model of the Savonius wind turbine, experimental tests were carried out in the laboratory of Fluids and Hydraulic Machines of the Technological University of Pereira. Every bit an important effect of analysis (simulation and experimental tests) a power coefficient of 0,two was obtained and shaft mechanical ability varies with cubic velocity current of air. Power over 100 W tin be reached with sweep area ane kⁱⁱ and 10 m/southward velocity turbines.

Keywords: Savonius wind turbine, wind energy, wind speed, power coefficient, mechanical power.

Resumen: El presente proyecto de investigación se centra en el desarrollo de united nations aerogenerador de tipo Savonius, en el que inicialmente se realiza una revisión de la literatura para reconocer los parámetros apropiados para su diseño, como la turbulencia, la velocidad del viento y la densidad del aire, seguido de una metodología de diseño para lograr el Dimensionamiento mediante cálculo de resistencia y selección de materiales componentes, luego de haber definido el concepto final. Mediante el uso de herramientas computacionales como Solidworks, Inventor, Simulation Mechanical, la etapa de diseño se validó a través de la simulación para estudiar el comportamiento dinámico del fluido y los componentes se modelaron para evaluar su respuesta a las cargas de viento, verificando su resistencia. Posteriormente, de acuerdo con el modelado, se obtuvieron los planos detallados de los componentes de la turbina, con los cuales fueron ensamblados. Finalmente, teniendo en cuenta el modelo físico del aerogenerador Savonius, se realizaron pruebas experimentales en el laboratorio de fluidos y máquinas hidráulicas de la Universidad Tecnológica de Pereira. Como resultados importantes del análisis (simulación y experimentación) se obtuvo que el coeficiente de potencia de la turbina eólica tiene un valor de 0,2 y la potencia mecánica en el eje de la turbina varía con el cubo de la velocidad del viento. Con turbinas de este tipo se pueden lograr potencias mayores a 100 W con área de barrido de 1m2 y velocidades de viento de 10 m/s.

Palabras clave: Turbina eólica Savonius, energía eólica, velocidad del viento, coeficiente de potencia, potencia mecánica.

I. INTRODUCTION

Current of air free energy is a renewable energy source which can be exploited to transform information technology through mechanical devices such as a air current turbine, where it converts the kinetic energy of the wind into mechanical energy of the axis [ane][2]. In that location are mainly 2 large groups of air current turbines that have been designed for such procedure and are classified according to the orientation of the turbine shaft. They are vertical centrality turbines and horizontal centrality turbines [3]. The horizontal centrality turbines that are found in the majority of wind farms are constituted past: foundation, belfry, gondola with power train, rotor and paddles.

According to the Guide on Mini-Wind Engineering science [four], in the instance of horizontal axis current of air turbines, the rotor can be windward, that is, in the direction of air current incidence in front of the tower, or to leeward, in which case the rotor is located behind the tower in the ascendant direction of the wind. Most of the current of air turbines are rotor to windward of the tower, which means that they require some guidance system. In the example of a downwind rotor, the rotor is self-orientating, which simplifies its design.

Horizontal centrality turbines are more efficient than vertical axis turbines, are more proven, are cheaper and at that place are many products to choose from. Yet, they have the difficulty of supporting the continuous orientations and their efficiency is reduced by operating in a turbulent regime.

Vertical centrality turbines are oriented in the predominant wind direction due to their symmetry, are less sensitive to high turbulence conditions and produce less vibration, these weather condition brand them platonic for integrations in residential, urban and fifty-fifty buildings [5]. On the other hand, their efficiency is lower compared to horizontal centrality and they are non very proven since they are now in full development. At that place are two types of vertical turbines, those based on drag and those based on elevator. The first one is less efficient, only usually less robust.

Within the vertical axis turbines are the Savonius type turbines which are used to convert the wind power in torque on a rotating axis. "The vertical axis turbines were invented by the Finnish engineer Sigurd J. Savonius in 1922", they can offset with a slow air current velocity, being very easy to manufacture; Information technology has a small turning speed and its operation is relatively low.

The enquiry work emphasizes Designing the concrete components of a wind turbine blazon Savonius based on the design parameters of this type of rotors and the parameters that characterize the utilise of wind energy such as wind speed, air density of a region and turbulence. Having the selected concluding concept and the sizing of the wind turbine, modeling and simulation of the rotor is carried out. Later on, the structure of the wind turbine is made according to the obtained plans and finally experimental tests are carried out in the laboratory.

II. Pattern parameters of the savonius blazon wind turbine

Several investigations [6], [7], [8] accept been made regarding the report of the functioning of the Savonius rotor from different geometrical configurations of its rotor. These studies have been made based on numerical computational analysis taking advantage of the use of CFD (Computational Fluids Dynamics) and experimental tests in wind tunnels. The different configurations that have developed over time, take looked for an improvement in the functioning of the aerodynamic behavior of the Savonius rotor. That is why the geometric configuration is fundamental in terms of its operation, the configuration that has been said for a Savonius rotor is determined by the following design parameters of the rotor:

• Rotor attribute ratio.

• Expanse swept by the rotor blades.

• Geometric shape of the blades (profile, length of rope).

• Human relationship of overlap and spacing between the blades.

• Number of blades and stages.

• Other additional components to the rotor construction (centrality, sail-flag consequence, support structure, etc.).

The geometric shape of the blades is going to take a semicircular profile which volition exist obtained from a PVC tube of 6 inches in diameter, keeping the traditional shape of the Savonius rotor blades. Effigy ane shows the contour of the blade with its dimensions.

Fig. 1.
Profile of the blade.
[7]

The overlap relation is a dimensionless parameter that relates the perpendicular altitude between the cantankerous and the eye of rotation with the chord line length which is given as (1)[8]:

(ane)

Where is the distance between the inner tips of the blades that have overlap and corresponds to the value of the semi-cylindrical blade bore which in turn coincides with the length of the rope. Effigy 2 schematizes the human relationship that has been said.

In this way, the overlap ratio is a design parameter of the Savonius rotor, several authors have studied the optimal overlap ratio in rotors with 2 blades, which is the detail instance of the present investigation. According to Menet, J et al. [vii] the overlap ratio in a two-bladed rotor is in the range of 0.xv to 0.iii times the length of the blade.

Fig. two
Schematization of the geometric parameters and the overlap ratio for a two-bladed rotor.
[viii]

The aspect ratio is a dimensionless parameter which involves the height of the rotor H and the bore of the circle that is formed when rotating the tips of the blades called diameter of the rotor D. Effigy 3 shows the geometrical values of the rotor where the attribute ratio can be seen.

Fig. 3.
Rotor aspect ratio.
[ix]

The equation that relates the superlative of the rotor H with the diameter of the rotor D, is given by (two) [9]:

(2)

The swept area of a rotor is generally defined every bit the projected area that is formed during the rotation of the blades. In the case of a Savonius-type rotor, the projected area corresponds to the expanse of a rectangle. This can be seen in Effigy four which schematically represents the projection of this area.

Fig. four.
Representation of the swept surface area of a Savonius rotor.
[6]

Thus the calculation of the swept area by the Savonius rotor will exist given by (iii)[10]:

(3)

The dimensioning of the terminal plates of the rotor is carried out based on the criteria proposed by Akwa et al. [6], which states that the thickness of the last plates must be minimum which is relative to the height of the rotor. It also recommends a value of ane.one times the value of the diameter of the rotor for the calculation of the diameter of the final plates . This is how the equation for the adding of the diameter of the final plates is given past (iv)[six]:

(four)

The value of the final plate thickness is influenced past the nature of the material and the moment of inertia of the rotor. Torres, Daniela M. [11] made a decision matrix to select a material of the blades and cease plates in which she selected as all-time option the 16 gauge galvanized sheet that corresponds to a thickness of 1.52 mm. The number of blades is a key structural parameter that weather the performance of the Savonius rotor, as stated above. Rotors of 2 blades take a greater variation in the torque induced in the axis with respect to those of three or more blades; this variation is presented, since for a two-bladed rotor the angle of separation between them is 180 °, in this mode every 180 ° a maximum torque is presented because the force received by the blades of the turbine is maximum at that point. This can be observed in the curve of torque confronting angle of attack presented by Hadi [10], which is shown in Fig. v.

Fig. 5
Variation of the static torque against the angle of attack of a Savonius turbine with two blades
[10]

Equally regards a rotor with three or more blades, the variation of the torque with respect to the angle of attack of the air flow tends to be more than constant, too allowing the handling of high-speed ratios at the tips. In the item case of the pattern of the rotor that is going to be carried out, a 2-bladed rotor was selected, since, although the torque presents a greater variation every bit a office of the angle of attack, the power coefficient curve in function of the speed ratio at the tips presents higher values of power coefficient. The following curve, Fig. 6, shows the comparison of the curves of the ability coefficient as a role of the wind speed.

Fig. 6
Power curves confronting current of air speed of a rotor of two, 3 and 4 blades
[9]

The Savonius rotor stages correspond the superimposition of simple Savonius rotors where they are out of phase at a certain angle [12], which is observed in Fig. vii.

Fig. seven.
Savonius rotors with different stages
[12]

For the present design a two-stage rotor is considered, since multiple stages are considered mainly for two-bladed rotors, in addition to the advantages of the reduction in moment fluctuations.

Fig. eight shows the ability coefficient as a function of air current speed for 2-stage rotors with 2, 3 and 4 blades.

An initial parameter to bear out the blueprint of the turbine is the speed of the free current of air current. That is why the location of the turbine is important. Co-ordinate to the Atlas of the Current of air [13], the average wind speed for the municipalities of Guática and Quinchía is approximately viii m/s. These sites are suitable places inside the department of Risaralda for the location of a Savonius current of air turbine, given its proximity and which can become test sites for this blazon of wind turbines. The average almanac wind speed at the Technological Academy of Pereira according to the meteorological unit is 0.77 m/s and co-ordinate to data collected by Torres D [11] the boilerplate annual speed of the meteorological unit of the Mundo Nuevo neighborhood is 3.81 m/s for the yr 2014. Afterward having made the analyzes of the sites mentioned above, a current of air speed of is set as the design parameter value, so that the turbine may be suitable for experimental testing in any of the afore mentioned sites.

Fig. 8
Power coefficient curves versus wind speed for a 2-stage rotor with 2, 3 and 4 blades
[ix]

The Tip Speed Ratio TSR (λ) [14] is a dimensionless parameter that relates the tangential speed of the tips of the blade with the speed of the complimentary wind electric current, in addition to representing the behavior of a particular type of a wind turbine, which is applicative for the VAWT (Vertical Centrality Wind Turbine) and HAWT (Horizontal Axis Wind Turbine), the TSR is referred to (5).

(5)

Where Ω is the angular velocity of the rotor, R is the distance from the center of rotation of the rotor to the tip of the blade. The Reynolds number is a dimensionless parameter used in the report of fluid flow through turbomachinery and flow systems, which relates inertial forces to viscous forces [12]. For a Savonius type wind turbine the Reynolds number is divers in equation (6).

(6)

Where ρ is the density of air, is the velocity of the free wind electric current, D is the bore of the rotor and μ is the dynamic viscosity.

The Reynolds number plays a very important role in the wind tunnel experimentation of wind turbines when evaluating their aerodynamic performance, authors such as Niaz [xv] conducted a study regarding the influence of the Reynolds number on the aerodynamic performance of a three-bract Savonius turbine with unlike overlap ratios in which it is expressed that: for high Reynolds numbers the modeled turbine without overlapping radius generates meliorate aerodynamic coefficients, on the other hand for low Reynolds numbers the model with a radius of moderate overlap generates better results.

III. DESIGN OF THE PHYSICAL COMPONENTS OF THE SAVONIUS Type WIND TURBINE

The flow of air through the rotor induces forces on the blades and the different elements that make up the support structure. The decision of the loads due to air flow is based on studying the behavior of the flow and applying the different theories that are derived in the analysis of momentum. This is how, the analysis of the different forces that act on a turbine is convenient to treat separately by doing an aerodynamic assay and then consider the forces that are transmitted betwixt the different elements.

According to the established design parameters, the component parts by which this device volition exist equanimous are listed:

• 4 semicircular blades.

• iii Final dishes.

• Turbine rotor shaft

• Support structure of the rotor.

• 2 roller bearings.

The following is a cursory description of the equations used in the design of the physical components of the turbine:

Design OF THE ROTOR: The tree design includes the following stages according to Vanegas, Fifty [16]:

• Material selection.

• Constructive design.

• Verification of resistance: Static, to fatigue and dynamic loads.

• Verification of the rigidity: deflection by bending and slope of the elastic and deformation by torsion.

• Modal assay.

Selection of shaft material. The nigh commonly used material in the industry of shafts is steel with low or medium carbon content. This cloth is recommended for the resistance of dynamic loads since it has fatigue limit and makes it suitable to support many load cycles. If additional properties such equally corrosion resistance are required, a steel whose properties permit resistance to the required characteristics must be selected.

Adding of rotor's weight. The determination of rotor's weight is made from the sum of the individual weights of each of the component elements.

The blades as defined in the preliminary design function, will be made of PVC material, the last plates that brand up the rotor from AISI / SAE 1020 Cold Rolled steel canvass and the panels that are part of the rotor of acrylic fabric. The total weight of the rotor is determined past (vii).

(7)

Calculation of the bore of the rotor shaft. The adding of the diameter of the rotor shaft will be made based on the theory of shaft blueprint recommended by Vanegas, 50 [xvi]. Since a shaft performs a rotating move, the loads information technology must support are variable over fourth dimension. That is why the blueprint equations of the Fatigue Theory are applied. In shaft fatigue analysis there are three methods which allow to calculate the shaft diameter required to adequately resist dynamic loads. These methods are the following:

• Von Mises method.

• Method adopted by Faires.

• ASME method.

The Von Mises method [16] is practical for this case after the different aerodynamic loads in the rotor have been adamant, from which the required diameter of the shaft can be obtained to support dynamic loads over time, this is shown below in (8).

(8)

Where the stresses _T and _D can exist calculated like this:

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It is of import to clarify that several checks of the resistance of a shaft must be made such every bit resistance to vibrations, rigidity, modal analysis, etc., as previously established.

Selection of air current turbine bearings: Based on the diagrams of shear forcefulness and angle moment, it can be determined the radial loads that the supports of the shaft must bear, that´s to say the bearings. In improver, the bearing located in the lower part must support the axial load that corresponds to the weight of the rotor. Therefore, the values of the reactions in the supports of the tree are:

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Determination of the equivalent radial dynamic load: Because of the bearings supports A and D, back up radial loads and axial loads, it is necessary to convert these load values into a single radial load value that would have an effect on the life of the equivalent bearing to the actual load practical, this load is known as "equivalent radial dynamic load " [17], which is determined past (9).

(9)

F_r : radial actual load [Northward], F_a : axial bodily load [N], X: radial load factor, Y: axial load factor.

Blade resistance evaluation: As indicated in the preliminary design, the blades are manufactured from a PVC pipe of 6 in., Based on these dimensions and material the bract'due south resistance must be evaluated, and so for its analysis it is take the blade that is in the lower phase being this the most critical to support drag forces and weight loads. According to the loading organization and finding the most critical section, verification of resistance to tearing and burdensome was carried out:

° Calculation of tear stress [xvi]: It is determined with (x):

(x)

b₁ : Distance from the edge of the blade to the periphery of the hole [m], it is obtained of the planes, 50 ₁ : Thickness of the material to exist evaluated [1000].

° Crushing resistance [xvi]: Burdensome resistance is determined with (11):

(11)

Design of the rotor bolts [16]: The fastening elements that are used to join the blades with the final plates and the shaft with the blades are bolts subjected to static loads, so design theories for combined static loads are practical. The Octahedral shear stress Theory is applied to 1 of the points subjected to normal stress and the other subjected to shear stress by ways of the equation 12.

(12)

Pattern OF THE STRUCTURE: The structure of the wind turbine will be composed of 2 trusses and six beams of which four are loaded beams and these supports the rotor, the other two beams are unloaded beams equally they provide stability and rigidity to the construction. This must provide resistance to the loads to which the turbine will be subjected (air current loads, weight loads of the same structure and the rotor), rigidity, depression deflection in the elements and minimum turbulence of the air flow that enters the rotor. Since the structure will exist formed past two lateral trusses joined by beams, all its component elements must be designed, so the design of the construction is focused on the analysis of the trusses, analysis of the beams and afterward the design of the Connection elements.

Loads that the structure supports. The main element of the wind turbine is the rotor to be this one, the component that supports different types of loads that in turn transmit them to the construction, on the other paw, the structure itself generates loads (own weight of this), that is why all possible loads must be considered. Initially the own weight of the structure is determined.

Truss design. The blueprint of the truss consists of the dimensioning of its structural profiles evaluating their behavior to resistance, stability and deflection. The geometric shape of the truss is composed of structural profiles interconnected in nodes by ways of brackets, which is shown in Fig. nine.

Fig 9.
Profile of the truss with nodes named according to the given classification in Autodesk Simulation Mechanical (measurements in mm).
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A free-body diagram of the structure is shown in Fig. 10.

Fig 10.
Complimentary body diagram of the truss
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Fig 11
Structural analysis of the truss using the calculator tool Autodesk Simulation Mechanical
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The analysis of the truss is then carried out by ways of the calculator program Autodesk Simulation Mechanical, which provides the numerical values of the reactions in the supports, the internal loads to which each chemical element is subjected (structural profile) and the way in which the truss may become plain-featured. Fig. xi shows the analysis of the truss, which shows the centric internal loads of each element, likewise they are numbered and indicate the elements and nodes past means of numbers.

Pattern of the elements or structural profiles of the truss. Based on the tensile or compression forces that back up the elements of the debate, we proceed to the determination of the stresses acquired by internal loads in each element, considering that each element that forms the structure supports centric loads that generate traction and compression normal stresses [16]. Since the structure does not support alive loads, its size is minor compared to roof structures, and since near of the loads are dead, information technology is designed from the normal stress equation given past (13).

(thirteen)

South_E : Normal stress that support the element [Pa], F_A,I : internal centric load in the chemical element [N], A_E : minimum area of the transversal section of the chemical element [m2].

The design equation of the elements subjected to simple static loads is given by the equation xiv:

(xiv)

Where Due south is the maximum stress to which the element is subjected. This equation can exist used with the yield stress or with the ultimate stress of the material, in this example the pitter-patter resistance is considered in equation fourteen in society to avoid failure due to plastic deformation.

Blueprint of the loaded beam. The design of the loaded beam is made based on the pattern equation presented to a higher place, where the loads supported by the beam produce normal bending stresses. Observing the bending moment diagrams, the critical point is in the centre of the axle where the bearing is supported.

Calculating the normal stress, it has:

(15)

The design of the connexion elements of the construction is not presented, but all its dimensioning is as well important for the structure office.

Modeling the current of air turbine past using the solidworks computational tool: the entire design process of the physical components of the wind turbine was presented based on the awarding of the dissimilar design theories for the dissimilar load conditions of the component elements. Thanks to the design procedure, the necessary dimensions of the component elements were determined to allow an acceptable mechanical resistance to the loads, minimum deformations and stability in the support structure, as well as the selection of the relevant materials of each element, connectedness forms or union, functionality, aesthetics and manufacturing costs. The dimensions thus determined, and the shape of the elements were modeled by using the Solidworks computational tool. The modeling process consists of obtaining 3D of each component element giving it its corresponding shape and the required dimensions. Subsequently, the assembly procedure is passed through the tools provided by the program, such equally positional relationships. The general associates of the current of air turbine is presented in Fig. 12.

Fig. 12.
Iii-dimensional view of the general assembly of the wind turbine.
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Simulation of air menses through the rotor of the Savonius air current turbine: Initially a dynamic simulation of the wind turbine rotor is executed, for this information technology is required to take the solid modeling of the rotor and once this is obtained, a volume must be divers of control which encloses the rotor, and information technology is there where certain border conditions are established equally the dissimilar thermodynamic properties (Pressure, Temperature, Enthalpy, etc.). Some other region of analysis is the rotating region in which the surface objectives are divers, understood as thermodynamic backdrop or dynamic variables that are desired to exist ascertained during the development of the assay. The ambient pressure and the boilerplate temperature of the identify were respectively defined every bit 86 kPa and 21 ° C, in improver the wind speed for the analysis is handled with eight m / southward, the aforementioned with which the blueprint process was carried out.

The pressure gradients equally shown in Fig. xiii in the dissimilar concave and convex parts of the rotor generate resultant drag forces in each portion of the rotor which acting on a distance produce a net torque that in turn allows the rotation of the rotor. To obtain a improve appreciation of the force per unit area distribution in the rotor and a closer approximation, an external menstruation analysis with the static rotor is performed.

Fig 13
Pressure distribution in the rotor in external flow.
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In the previous figure it can exist seen that the highest force per unit area (yellow lines) is given on the concave part of the rotor blade. The distribution of pressures tin can also be seen in the flooring program shown in Fig. fourteen.

Fig 14.
Pressure distribution in the rotor aeroplane.
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Analyzing the distribution of pressures, it is observed that the highest pressure is produced on the concave side of the blade and in the convex part a lower pressure is distributed. This differential of pressure and consequently a deviation in the drag forces on the blades causes the torque generated by the drag force on the concave side to be greater compared to the torque generated past the drag force on the convex side, assuasive that the rotation of the rotor is given. Too, for this case, the distribution of speeds in the flooring programme for the static case of the rotor is presented in the following figures.

In the Fig. 15 and xvi, information technology is observed that the geometric configuration of the Savonius rotor (overlap) contributes to the air circulation from ane blade to the other one, thus increasing its induced torque, since part of the circulating air increases the elevate force in each concave part. Through the analysis, other dynamic variables and thermodynamic properties were determined, such as the forces on the blades, the torque, and the density of the air. The following table provides the value of the dynamic variables and thermodynamic backdrop.

Fig xv.
Speed distribution in the rotor airplane for φ = 0 ° upper phase.
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Fig 16
Distribution of speeds in the rotor plane for the position φ = ninety ° lower stage.
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Table I

DYNAMIC VARIABLES AND THERMODYNAMIC Properties Determined Past DYNAMIC FLUID Assay FOR THE ROTOR WITHOUT PANELS.

Dynamic variable and thermodynamic property	Minimum value	Maximum value	Mean value	South.I Unity
Total pressure	86036.76	86036.77	86036.77	Pa
X- velocity	0.004	0.005	0.004	1000/due south
y- velocity	0.018	0.019	0.018	m/southward
z- velocity	seven.483	7.484	vii.483	m/due south
Normal forcefulness in Z	seven.4	seven.421	7.413	N
Density	1.02	1.02	ane.02	kg/grand^3
Static torque (centrality y)	0.395	0.396	0.396	Nm
Dynamic torque (axis y)	0.233	0.272	0.242	Nm

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According to the results obtained presented in the table I, it can be expressed that the air velocity in the rotor presents only one predominant component along the coordinate axis z (current of air incidence) and in the rest the values are null, meaning this there is a 1-dimensional flow. Due to this, the forcefulness exerted past the air flow on the rotor has a component along the coordinate axis z, in the direction of air period, the other forcefulness components are zilch. As for the torque, information technology presents a value of in the negative direction of the coordinate axis.

V. Physical Associates OF THE SAVONIUS Wind TURBINE

The process of cutting with frame-saw was used to requite the required dimensions to the different structural profiles. These dimensions were obtained from the design process, and were reflected in the plan of the structure, where said measures were guaranteed with the use of the meter and squares. In the same manner, this tool was used to cut the angles of the structure, the rotor and the PVC tube to obtain the blades. The mechanical shear was used throughout the process of cut the gills to requite the required dimensions. On the other hand, the circular shape of the concluding plates was obtained thank you to the oxyfuel process. Table Ii presents the process of cutting metals by oxyfuel.

TABLA II

MATERIALS AND MECHANICAL ELEMENTS USED IN THE Assembly OF THE WIND TURBINE.

Blazon of element	Dimensions and specifications	Material	Obtention process
Tubular structural contour of foursquare section	26 mm x 26 mm x 6 m length	Steel AISI SAE 1020	Cold rolled (cold lamination)
Steel plate	three mm thick	Steel AISI SAE 1020	Cold rolled (cold lamination)
Bending connector structure	38 mm (equal wings) x ane m length, thickness 2 mm	ASTM A36	lamination
Angle connector bract end plate	20 mm (equal wings) 10 1.five mm thick	ASTM A36	lamination
Union bolts of the structure	Nominal Diameter 1/four", number of threads per inch 20	Steel AISI SAE 1020	Industrial process
Rotor shaft	Bore five/8 "	Steel AISI SAE 1020	Cold lamination
Final dishes	14 gauge	Steel AISI SAE 1020	Cold lamination
blades	vi "in diameter 10 one m in length.	PVC	Industrial procedure
Console	Panels of 490mm x 300mm x 2.5mm thickness	Acrylic	Industrial procedure
bearing	UCF 201-8	steel	Industrial process
hinge	Ref. 3 IMDUMA	steel	Industrial process

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The main shaft of the rotor required certain dimensions co-ordinate to its pattern procedure. The tree was and then submitted to the turning procedure with its initial dimensions to bring information technology to said dimensions. During the mechanization of the tree, information technology became necessary to use a bezel to back up the tree due to its length of 1.5 m. The use of the calibrator and micrometer as measuring elements was essential to guarantee the required dimensions of said mechanical element.

The drilling operations enabled the drilling of the holes in structural elements, brackets, angles, blades, tree and cease plates. These holes volition allow through them pass the union bolts of the structure and the rotor, where the adjustment between commodities and pigsty is a fit with clearance. It became necessary to make different assemblies to carry out all the various drilling operations required. The associates that was carried out for the drilling process in the laboratory of Machines

Subsequently carrying out all the manufacturing operations required, the final assembly is carried out, which can be seen in Fig. 17

Fig 17.
Assembly of the wind turbine.
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VI. EXPERIMENTAL TESTS OF THE SAVONIUS Wind TURBINE

Experimental tests were performed on the current of air turbine without panels for which measurements were made of current of air speed, angular speed of the rotor, and static torque respective to different wind speeds. The tests were carried out in the wind tunnel of the Laboratory of Fluids and Hydraulic Machines of the Technological University of Pereira with the collaboration of Eng. Yamal Mustafá Iza Chiliad.Sc., which through the use of a frequency inverter tin can be varied its athwart velocity, which means having a variable wind speed. To carry out the measurement of the experimental data during the tests, the following measurement devices were used:

° Anemometer model AM-4206, resolution for current of air speed measurement of 0.01 m / south and resolution for temperature measurement of 0.1 ℃. The wind speed information is measured at 70 cm from the rotor.

° LT Lutron DT 2236 tachometer, resolution 0.1 rev / min.

The obtained angular velocity curve is shown as a office of the wind speed in Fig. 18.

Fig 18.
Athwart velocity as a office of current of air speed.
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The bend obtained from torque equally a function of the wind speed is shown in Figure 19. For this case the torque is measured statically, with the difference that in this example the wind affects the rotor to different speeds, achieving balance of the rotor with the addition of different counterweights.

Fig 19.
Torque as a function of the wind speed for the rotor.
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Fig. xx shows the mechanical ability as a part of the wind speed, for this case the mechanical power was determined theoretically from the experimental data of static torque and angular speed of the rotor corresponding to table 8.three. The determination of the mechanical ability is determined past (16)

(sixteen)

Fig 20.
Mechanical ability as a role of wind speed.
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VII. ANALYSIS OF EXPERIMENTAL RESULTS

Co-ordinate to the tabulated experimental data, the post-obit tin be expressed:

• It can be observed in the curve of figure 18 that there is a linear relationship between the wind speed and the angular speed of the rotor, thus confirming the TSR (Tip Speed Ratio). On the other hand, the angular velocity of the rotor without panels is much higher compared to that obtained from the rotor with panels, because the panels increase the inertia of the system and besides restrict movement.

• The behavior of the information of the curve of figure 19 of torque every bit a role of the wind speed have a functional human relationship of order 2.

• The graph in figure 20 shows the beliefs of the mechanical power data as a function of the air current speed, in which a cubic tendency is observed. This is what is expected since theoretically the mechanical ability of a wind turbine varies with the cube of the wind speed.

8. CONCLUSIONS

• The parameters of the wind energy were characterized, peculiarly the variability of the air current speed in the whole Colombian national territory.

• The information taken from the meteorological unit of measurement of the ceiling of the Kinesthesia of Mechanical Engineering showed that the boilerplate wind speed is 1 m / s for this reason this site is not suitable for this type of wind turbine. Places in the coastal areas of Colombia represent a good wind potential for the use of this type of energy.

• The design of the air current turbine was based on the scientific articles investigated, theories studied and the experiences of other authors.

• Applied design theories allowed to select the advisable materials and the required dimensions, to obtain a physical model that guarantees the operating weather condition based on which it was designed.

• The modeling of the current of air turbine was developed using the Solidworks calculator tool, based on the sizing obtained through the design process.

• The analysis of the behavior of the flow immune to know the distribution of pressures in the blades, the issue of overlap, the velocity field on the rotor and the torque generated by the drag forces.

• The different manufacturing processes required were carried out in guild to acquit out the physical assembly of the Savonius wind turbine.

• Experimental tests of the turbine with the axial fan of the wind tunnel were adult in the laboratory of Fluids and Hydraulic Machines of the Faculty of Mechanical Engineering of the Technological Academy of Pereira.

Acquittance

We thank and admit the corking work that each of the teachers, administrators, workers and students of the Technological Academy of Pereira have done for providing u.s. with their knowledge, education, fourth dimension, service, collaboration and friendship during the phase of bookish formation and Professional every bit Mechanical Engineer.

REFERENCES

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[7] J. L. Menet, Northward. Bourabaa. "Increase in the Savonius rotors efficiency via parametric investigation," Ecole Nationale Superieure d'ingenieurs en Informatique Automatique Mecanique Énergetique Électronique de Valenciennes ENSIAME, [online].Available: http://educypedia.karadimov.info/library/23_1400_jeanlucmenet_01.pdf.

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Author notes

ane

Edgar Alonso Salazar Marín
Autor

was built-in on June 6, 1973 in Santa Rosa de Cabal. (Risaralda / Colombia). He´s Mechanical Engineer and did doctored studies in Polytechnical University of Catalonia- Spain (2003-2007), He has main´s studies in mechanical applied science of Andes University- Bogotá (1997-1998) and Primary in Automatic Systems of Production – UTP (2002-2004). He worked every bit researcher in Coffee Research National Center (Cenicafé) from 1999 to 2000.

He has worked as professor in Engineering Faculty on Technological University of Pereira since 2000 and he´s developed dissimilar projects about renewable energies, similar Solar systems (thermal and photovoltaic), solar vehicles and conversion from combustion vehicles to electrical vehicles.

2

Andrés Felipe Rodriguez Valencia
Autor

was born on September fourteen, 1992 in La Victoria Valle (Colombia). He completed his undergraduate studies in Mechanical Engineering (2010-2016) at the Technological University of Pereira (UTP). During the realization of the career, he was bookish monitor of the section of mathematics and monitor of the laboratory of fluids and hydraulic machines. At a professional level, he worked in the maintenance expanse at the visitor Trapiche Biobando Southward.A.S, where the company'due south assembly activities were supported, in the expanse of ​​extraction and processing. He worked at Accedo Colombia S.A.Southward in the commercial sales part of the visitor. In 2017, he started as Professor of the Faculty of Mechanical Engineering, has directed the courses of Static and Hydraulic Machines and Fluids Laboratory. With the Department of Mathematics, he has guided the Linear Algebra courses. He is candidate for the primary'southward degree in Mechanical Engineering science in the line of manufacturing and pattern processes of the same university, where he graduated from, since 2017.

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